Packing towers are used to transfer a gas-liquid stream or a liquid-liquid stream by means of continuous contact. Tower packings in the packing tower play a key role in mass or heat transfer, and the flowing passages of the gas-liquid stream or the liquid-liquid stream, as well as the transferring method are determined by the tower packings. There are two types of tower packings, including a random tower packing and a structured tower packing. The random tower packing is composed of a plurality of tower packings packed in the packing tower randomly. As passages for gas and liquid in the random tower packing is not straight, the flowing distance for the gas or liquid stream in the packing tower are long. Further, the random tower packing holds a large quantity of liquid, such that a contact time between the gaseous phase and the liquid phase of the stream is long, which increases the turbulent intensity of the contacting surface between the gaseous phase and the liquid phase of the stream, and finally improves the mass or heat transferring efficiency. As described above, the random tower packing is advantageous in an absorption process with chemical reactions or with a condition of a high pressure system or a large quantity of liquid loading. However, the random tower packing has a small specific surface area which causes a great resistance during the flowing of the stream. In this condition, a diameter-height ratio of the random tower packing is increased so that the random tower packings may be achieved regularly as far as possible. In addition, a wall of the tower packing is further broadened in order to reduce a pressure drop of the random tower packing and improve the processing capacity and efficiency of the random tower packing.
The structured tower packing is composed of a plurality of tower packings arranged in the packing tower regularly and each having a uniform shape. The structured tower packings define a regular passage for the gas stream and the liquid stream, such that the pressure drop therein is small. Further, compared with the random tower packing with an equal specific surface area, the structured tower packing holds a smaller quantity of liquid and has a higher processing capacity.